1. Field of the Invention
The invention relates to improvements introduced into the functional attachment system for osteosynthesis, by means of compression plates.
2. Description of the Prior Art
The use in osteosynthesis of various types of plates is known for exerting a strong pressure on the two parts of the bone on both sides of the fracture. One of said types of plates makes use of auxiliary systems consisting of a turnbuckle, which is joined by means of screws to one of the parts of the bone in such a way that this turnbuckle forces the bone into which the plate is screwed closer to the other part of the bone so that they press against one another, in addition to which said plate is also joined with screws to the other part of the bone, at which time the turnbuckle is removed.
Another known system for functional attachment for osteosynthesis, created in fact by the inventor of these improvements, is based on the mechanical or biomechanical principle of providing the compression plates with a special device that slides parallel to the major axis of the bone in such a way that the muscular contraction is converted into an impacting or compression at the focus of the fracture between the fragments equal in magnitude and opposite to said contraction. A similar effect is produced by the action of "muscle tone," which is a state of minor permanent contraction, or by the action or gravity and load. The principle is thus carried out whenever mechanical devices are used in internal osteosynthesis that neutralize or tend to neutralize all angular, lateral or rotational movements, with movement in the direction of the bone axis remaining free. Hence this is osetosynthesis in which the "bridge," with a solid osseous anchor, is formed of one or two parts sliding together.
All current osteosynthetic systems are based on achieving absolute rest for the focus, including under compression at the line or focus, in order to increase stability by means of endless screw systems, internal tension created on plates, etc.; but in all these techniques compression is virtually invariable and its magnitude entirely empirical.
The compression plates used in the aforementioned systems all have major drawbacks, among which may be cited the need for a meticulous and complicated application as well as the need for precise machining. Despite all this satisfactory results that would justify such requirements have not been achieved.